v8...how long will the tranny last?

[mcompton1973]

Hey there.
We have narrowed it down to 2 mountys.
both v8's

we know on a v6 x that the tranny is only good for about 100-120k miles without needing some kind of major tranny work (I KNOW there are some of you with 150-180k and never had a prob with your tranny but on average from what i have read and seen.....120k...is ready for some tranny work.)

I am wondering on a v8 if there is a magic number that is similar. In other words....does the v8 tranny seem to go out at 150k or 120k or what? I was told it was a stronger tranny than what is in the v6. What tranny would be in a 97 mounty? First thing I will do is flush the tranny fluid and replace it. Should I stay with dino fluid or go to syn?

Thanks.

 

[section525]

The 97 Mounty will have the 4R70W tranny which is pretty darn tough. Mine ran flawlessly for the 135k I used it. I still have it as a spare and it doesn't (seem like it) needs a rebuild anytime soon. Infact, I'm going to say that you shouldn't even be worrying about the life of your tranny cause you'll run the wheels on your Mounty before the tranny will go. Does that make you feel better?

If I had to give you a magic number.. it would be... 197k. Hows that?

 

[BradE.]

The 4R70W is a pretty strong tranny. It's also used in F150's, Town Car's, Crown Vic, and Police Intercepters. That does not however make it maintenance free. The 4R70W's are know for a shuddering problem with the torque converter. There is a TSB that updates older 4R70W trannys requiring Mercon fluid to now use Mercon V. This was done to aid in the shuddering problems. If all else fails, there is a TSB saying the PCM must be recalibrated to get rid of the shudder. Some trannys have the shudder, some don't. I would not let that scare you away because it can be fixed with either Mercon V or a PCM reflash at the dealer. Better yet, when you test drive it, see if you notice shuddering at speeds of 35-45 MPH. If you do, adjust your offer to purchase accordingly.

Other than that, it's a pretty strong tranny. Change the fluid ever 25K miles and it will last a very long time. I would not get it power flushed, you can change most of it yourself. The 4R70W has a drain plug on the torque converter, so you can drain it and drop the pan and get about 90% of the fluid out. Plus, with the pan off you can replace the Tranny filter (Which is highly recommended, and most shops will not do this when they use a flush machine)

Good Luck!

 

[iforgited]

I had a 95 CV with the 4R70W Tranny in it with 275K on it and it ran like a charm it was on its second engine but the Tranny was tough as ever. It did have a slight shutter problem but Ford makes this friction modifier that you dump in the tranny the shutter goes away. I would highly Recommend this tranny!

 

[Jason_25]

I have heard from multiple sources that the 4R70W shuddering is due to loose valve body bolts that can be easily retightened.

 

[james t]

you are correct, Jason.

 

[BradE.]

The shudder on many 4R70W's is related to the torque converter chatter. This is because these trannys run hot, and the fluid's friction modifier brakes down causing the chatter. Ford changed over to Mercon V on the 4R70W trannys to help correct the problem (better heat resistance, and more friction modifier). In cases where the Mercon V does not help the PCM needs to be reflashed so it will correct the problem. It changes the shift points so the converter does not "hunt" between 3rd and 4th, thus the chattering.

It really has nothing to with the valve body bolts. The valve body bolts cause more hard shifs, not the shuddering issue.